Cryogenic fluid discharge muffler

ABSTRACT

A cryogenic discharge muffler wherein the operation thereof depends on a small amount of cryogenic liquid being retained in a sump portion of the muffler assembly. The liquid boils away during off-cycles and prevents ice buildup on the muffler. The muffler is intended to disperse cryogenic liquid so that the liquid will evaporate on contact with air and thereby reduce or substantially minimize the hazard generally associated with the discharge of cryogenic liquids.

United States Patent Kozlowski [54] CRYOGENIC FLUID DISCHARGE MUFFLER [72] inventor: Joseph Z. Kozlowski, Jasper, Ala.

[73] Assignee: The United States of America as represented by the United States Atomic Energy Commission [22] Filed: Feb. 6, 1970 [21] Appl.No.: 9,299

[52] US. Cl. ..62/45, 62/296, 220/44 A [51] Int. Cl. ..Fl7c 7/02 [58] Field of Search ..165/135, 136; 60/29; 62/45,

62/55, 55.5, 296; 220/85 VR, 85 VS, 44 A; 181/53, 68, 70; 55/466, 441, 267, 385

[56] References Cited UNITED STATES PATENTS 1,459,797 6/1923 Parolini et al 6()/29 X 51 Mar. 14, 1972 Thompson et al. ..60/29 X Hubrich ..18l/58 Primary Examiner-Meyer Perlin Assistant Examiner-Ronald C. Capossela Attorney-Roland A. Anderson [5 7] ABSTRACT A cryogenic discharge muffler wherein the operation thereof depends on a small amount of cryogenic liquid being retained in a sump portion of the muffler assembly. The liquid boils away during off-cycles and prevents ice buildup on the muf- Her. The mufiler is intended to disperse cryogenic liquid so that the liquid will evaporate on contact: with air and thereby reduce or substantially minimize the hazard generally associated with the discharge of cryogenic liquids.

7 Claims, 3 Drawing Figures CRYOGENIC FLUID DISCHARGE MUFFLER BACKGROUND OF THE INVENTION The invention described herein was made in the course of, or under, Contract No. AT( 1 ll)GEN-8, with the United States Atomic Energy Commission.

Cryogenic liquids (liquid nitrogen, air, hydrogen, helium, etc.) are used in many laboratories for supercooling materials and providing good operation of cold traps in vacuum systems. Many of these applications use automatic filling devices which maintain the liquid in the container at a desired level, such devices being on-off filling mechanisms. Because of the cyclic operation, there is intermittent discharge of the cold cryogenic gas from the container vent. If the automatic device malfunctions, the vent may discharge liquid which is at a very low temperature (320 F. for liquid nitrogen) and is a hazard to personnel and may damage adjacent equipment. During the off-cycle of these devices, ambient moisture condenses in the vent, building up a frost or ice formation which plugs the openings, whereby the discharge of gas during the on cycle of the device is prevented.

SUMMARY OF THE INVENTION The present invention is muffler and safety diffuser for attachment to the vent lines of cryogenic liquid containers, thereby providing safe and quiet discharge control of gas and liquid such that the liquid will evaporate on contact with air and thus reduce or substantially minimize the above-described problems associated with the discharge of cryogenic liquid.

Therefore, it is an object of this invention to provide a cryogenic fluid discharge muffler.

A further object of the invention is to provide a muffler assembly for safe and quiet discharge control of the gas and liquid in cryogenic systems.

Another object of the invention is to provide a muffler assembly for cryogenic fluids which prevents the formation of frost or ice on the discharge portions thereof, thus preventing plugging thereof.

Other objects of the invention will become readily apparent from the following description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view partially in cross section of a preferred embodiment of the invention; and

FIGS. 2 and 3 are partial cross-sectional views of other embodiments of the inventive muffler.

DESCRIPTION OF THE EMBODIMENTS The operation of the inventive muffler assembly depends on a small amount ofliquid being retained in the sump portion of the muffler. This liquid gradually boils off during the off-cycle of the filling device. This boiling action maintains a stream of dry gas discharging through the vent holes thus preventing frost and ice buildup which would plug the openings. If the fill device malfunctions and remains open continuously, the muffler fills with the cryogenic liquid. The vent holes disperse this liquid so that it evaporates on contact with the air, thus reducing the hazard and damage problem to a minimum.

Referring now to the preferred embodiment as illustrated in FIG. 1, the muffler assembly includes two sections, a primary diffusion section indicated generally at and a secondary diffusion section 11. The primary diffusion section 10 is composed basically of an inlet tube or conduit 12 adapted for connection to the discharged line of a cryogenic fluid container and which terminates in an inner housing 13 defining a liquid chamber or sump 14, an outer housing 15 positioned in spaced relation about inner housing 13 so as to define a gas chamber 16 therebetween and a downwardly opening cup-shaped baffle member 17 positioned about the upper portion of inner housing 13 and intermediate housings 13 and 15. Inner housing 13 is provided in the upper peripheral portion thereof with a plurality of apertures 18 which, in conjunction with baffle member 17 define a primary diffuser. Outer housing 15 is provided with a plurality of outlet or discharge ports or apertures 19 in the upper portion which provide fluid communication between gas chamber 14 and an outlet tube or conduit 20 which is coupled at 21 to an inlet tube or conduit 22 of the secondary diffusion section II.

In addition to inlet tube or conduit 22, the secondary diffusion section 11 includes a housing 23 to which tube 22 is connected at the upper end and which defines a diffusion chamber 24. Housing 23 is provided with an inwardly projecting bottom end portion 25 which defines a secondary or final diffuser, and a plurality of discharge ports or vents 26 about the lower end portion. The external surface of the inwardly projecting bottom end portion 25 serves as a heater well for a heating unit 27 which maintains the discharge ports 26 above freezing so that frost cannot build up on the ports and block them. The entire muffler assembly, diffusion sections 10 and l l, is completely surrounded by insulation material 28 except for the lower end portion of the secondary diffusion section housing 11 such that discharge ports 26 are uncovered.

In operation of the FIG. 1 embodiment, liquid enters the primary diffusion section 10 through inlet conduit 12 and is contained by liquid chamber 14, the gas in chamber 16 surrounding the liquid chamber 14 assists in insulating the liquid chamber and maintaining the desired liquid level therein. As pointed out above, the liquid in chamber or sump 14 gradually boils off during the off-cycle of the associated filling device which maintains a stream of dry gas discharging through the discharge or vent holes 26 in the secondary diffusion section 11. The primary diffuser (apertures 18 and baffle member 17) assures that little or no liquid will enter the gas chamber 16 during normal operation. The diffusion chamber 24 of secondary diffusion section 11 assures that liquid which might enter conduit 22 via apertures 19 in outer housing 15 will not discharge at the ports 26 even during overload conditions. The heater unit 27, as pointed out above, functions to prevent plugging of ports 26 by ambient moisture condensing thereat and forming frost or ice. A thermostat, not shown, can be installed on the exterior of the housing 23 defining diffusion chamber 24 to prevent overheating during standby or off conditions.

Tests conducted on the FIG. 1 embodiment have verified continuous operation thereof for substantial time periods without frosting or malfunction, thus clearly overcoming the prior problems discussed above.

The embodiments illustrated in FIGS. 2 and 3, and described in detail hereinafter, may, if desired, be utilized as illustrated or may replace the primary diffusion section 10 of the FIG. 1 embodiment by positioning a hollow annulus about the discharge ports thereof and connecting same to the inlet tube or conduit 22 of secondary diffusion section 1 1.

Referring now to the FIG. 2 embodiment, the muffler comprises basically a housing 30 having a diffusion cone 31 positioned therein and with the lower half thereof surrounded by insulation 32. Housing 30 is provided at the top thereof with an inlet tube 33, at the upper half thereof with a plurality of discharge ports or vents 34, and defines a liquid chamber or sump 35 in the lower half thereof. Diffusion cone 31 comprises a hollow body portion having a plurality of apertures 36 therein and a constricted nozzle portion 37, the operation of the FIG. 2 device being generally similar to that of the primary diffusion section 10 of the FIG. 1 device.

The FIG. 3 embodiment is similar in construction with the FIG. 2 device with the primary differences being in the addition of a second diffuser. The FIG. 3 muffler comprises generally a housing 40 and a pair of diffuser cones 41 and 42 positioned in spaced relation within housing 40 and interconnected by tubing 43. Housing 40 defines in the lower end portion thereof a liquid chamber 44, is provided at the upper end with an inlet conduit 45 and in the upper half thereof with a plurality of rows of discharge ports or vents 46. Thermal insulation 47 is positioned about the lower portion of housing 40. However, should it be desirable, a plurality of conducting fins may be substituted for the insulation 47 for inducing insulation frost buildup. Each of diffuser cones 41 and 42 include a converging section defining a nozzle opening 48 and 49, respectively, with the lower cone 42 being provided with a plurality of apertures 50. The provision of the two diffuser cones 41 and 42 provide better separation of the cryogenic liquid and gas, and assure discharge of gas only from the discharge ports 46 in housing 40.

In each of the embodiments, as set forth above, after the muffler unit reaches low temperature, cryogenic liquid will collect in the liquid chamber or sump thereof and gradually boils off during the off-cycle of the associated filling device which boiling action maintains a stream of dry gas discharging through the vent or discharge ports thus preventing frost and ice buildup which would plug these ports.

It has thus been shown that the present invention provides a muffler assembly for cryogenicfluid discharge which overcomes the prior hazard and damage problems relating discharge of cryogenic liquids, thus substantially advancing the state of this art.

While particular embodiments of the invention have been illustrated and described, modifications and changes will become apparent to those skilled in the art, and it is intended to cover in the appended claims all such modifications and changes as come within the spirit and scope of the invention.

lclaim:

1. A cryogenic fluid discharge muffler assembly adapted for use with on-off-type cryogenic systems for controlling the discharge of the gas and liquid comprising: a housing means, primary diffusion means positioned in said housing means, inlet means operatively connected to said housing means at the upper end portion thereof and adapted to supply cryogenic fluid thereto, said housing means being configured to define at least a liquid chamber means therein and being provided in the upper portion thereof with a plurality of discharge port means, means positioned about at least the lower portion of said housing means for insulating same, and secondary diffusion means operatively connected to said discharge port means in said housing means for fluid communication therewith, said secondary diffusion means being provided with discharge vent means for exhausting fluid therefrom, whereby cryogenic fluid retained in said liquid chamber means gradually boils off during the ofi-cycle of an associated filling device maintaining a stream of dry gas discharging through said discharge port means and said discharge vent means thus preventing frost and ice buildup from plugging said port and vent means.

2. The muffler assembly defined in claim 1, wherein said primary diffusion means comprises a body portion and a nozzlelike portion, said body portion being adjacent said inlet means and provided with a plurality of apertures therethrough and said nozzlelike portion terminating in a direction opposite said inlet means.

3. The muffler assembly defined in claim 1, wherein said plurality of discharge port means in said housing means consists of a pair of spaced rows of circumferentially positioned port means, and wherein at least a portion of said primary diffusion means is located intermediate said pair of spaced rows of port means.

4. The muffler assembly defined in claim 1, wherein said primary diffusion means comprises a pair of spaced diffuser cones, each of said diffuser cones including a converging nozzlelike end portion, said nozzlelike end portions being interconnected by tube means, one of said diffuser cones being provided with a plurality of apertures.

5. The muffler assembly defined in claim 1, wherein said housing means comprises an inner housing defining a said liquid chamber means, an outer housing mounted in spaced relation about said inner housing and defining therebetween a gas chamber means, said inlet means extending through said outer housing and terminating within said inner housing, said primary diffusion means comprising a plurality of apertures in the u pper portion of said inner housing and a baffle means positioned intermediate said inner housing apertures and said outer housing, said discharge port means being located in the upper portion of said outer housing, and wherein said insulating means is positioned about the entire periphery of said outer housing.

6. The muffler assembly defined in claim 5, wherein said baffle means comprises an inverted cup-shaped member positioned about the upper end portion of said inner housing and in spaced relation therewith, said inlet means extending through a bottom portion of said inverted cup-shaped member, side portions of said inverted cup-shaped member being positioned intermediate said apertures of said diffuser means and said discharge port means.

7. The muffler assembly defined in claim 1, wherein said secondary diffusion means comprises a housing defining a diffusion chamber therein, tubing means connecting said housing to said housing means for fluid communication therewith through said discharge port means, said housing being provided with an inwardly projecting bottom portion, the inner surface of said inwardly projecting bottom portion defining a diffuser means, said discharge vent means comprising a plurality of apertures in the lower portion of said housing, said inwardly projecting bottom portion of said housing defining on the external surface thereof a well for a heater unit, and insulation means positioned about said connecting tubing means and about said housing except the lower portion thereof adjacent said discharge vent means. 

1. A cryogenic fluid discharge muffler assembly adapted for use with on-off-type cryogenic systems for controlling the discharge of the gas and liquid comprising: a housing means, primary diffusion means positioned in said housing means, inlet means operatively connected to said housing means at the upper end portion thereof and adapted to supply cryogenic fluid thereto, said housing means being configured to define at least a liquid chamber means therein and being provided in the upper portion thereof with a plurality of discharge port means, means positioned about at least the lower portion of said housing means for insulating same, and secondary diffusion means operatively connected to said discharge port means in said housing means for fluid communication therewith, said secondary diffusion means being provided with discharge vent means for exhausting fluid therefrom, whereby cryogenic fluid retained in said liquid chamber means gradually boils off during the off-cycle of an associated filling device maintaining a stream of dry gas discharging through said discharge port means and said discharge vent means thus preventing frost and ice buildup from plugging said port and vent means.
 2. The muffler assembly defined in claim 1, wherein said primary diffusion means comprises a body portion and a nozzlelike portion, said body pOrtion being adjacent said inlet means and provided with a plurality of apertures therethrough and said nozzlelike portion terminating in a direction opposite said inlet means.
 3. The muffler assembly defined in claim 1, wherein said plurality of discharge port means in said housing means consists of a pair of spaced rows of circumferentially positioned port means, and wherein at least a portion of said primary diffusion means is located intermediate said pair of spaced rows of port means.
 4. The muffler assembly defined in claim 1, wherein said primary diffusion means comprises a pair of spaced diffuser cones, each of said diffuser cones including a converging nozzlelike end portion, said nozzlelike end portions being interconnected by tube means, one of said diffuser cones being provided with a plurality of apertures.
 5. The muffler assembly defined in claim 1, wherein said housing means comprises an inner housing defining a said liquid chamber means, an outer housing mounted in spaced relation about said inner housing and defining therebetween a gas chamber means, said inlet means extending through said outer housing and terminating within said inner housing, said primary diffusion means comprising a plurality of apertures in the upper portion of said inner housing and a baffle means positioned intermediate said inner housing apertures and said outer housing, said discharge port means being located in the upper portion of said outer housing, and wherein said insulating means is positioned about the entire periphery of said outer housing.
 6. The muffler assembly defined in claim 5, wherein said baffle means comprises an inverted cup-shaped member positioned about the upper end portion of said inner housing and in spaced relation therewith, said inlet means extending through a bottom portion of said inverted cup-shaped member, side portions of said inverted cup-shaped member being positioned intermediate said apertures of said diffuser means and said discharge port means.
 7. The muffler assembly defined in claim 1, wherein said secondary diffusion means comprises a housing defining a diffusion chamber therein, tubing means connecting said housing to said housing means for fluid communication therewith through said discharge port means, said housing being provided with an inwardly projecting bottom portion, the inner surface of said inwardly projecting bottom portion defining a diffuser means, said discharge vent means comprising a plurality of apertures in the lower portion of said housing, said inwardly projecting bottom portion of said housing defining on the external surface thereof a well for a heater unit, and insulation means positioned about said connecting tubing means and about said housing except the lower portion thereof adjacent said discharge vent means. 